The invention relates to a cap-shaped implant for implanting on a prepared stump of a femoral head. The implant is in the form of a ball section, having a flat base surface and a polar axis which is arranged in a perpendicular in relation to the base surface. According to the invention, a cavity is arranged in ball section which protrudes from the base surface, said cavity is rotationally symmetrical and comprises a hollow spatial axis which is arranged below an angle (a) which is different form zero in relation to the polar axis.